While reading the mother of all blogs, You Had Me At EHLO, I noticed that the Microsoft Office 2008 for Mac 12.1.4 Update is available to download and that it fixes an Entourage calendar issue (for those who don't know what Entourage is, think of it as the Outlook for Mac).
"This update fixes a calendar issue in versions of Microsoft Entourage that were updated with the Microsoft Office 2008 for Mac 12.1.3 Update. The issue prevents Exchange accounts in Entourage from sending meeting invitations and responses. This issue can occur when an Entourage identity is configured with more than one mail account. We strongly recommend that all Entourage users who installed Office 2008 for Mac 12.1.3 Update install this update."
Applies to: Office 2008, Office 2008 Home and Student Edition, Office 2008 Special Media Edition, Word 2008, Excel 2008, PowerPoint 2008, Entourage 2008.